1. Field of the Invention
The present invention is generally concerned with fitting a holding part onto an eyeglass lens to be worked on, for example trimmed, the holding part being adapted to adhere to the lens temporarily, by means of a sucker, for example, to enable the lens to be fitted to and locked in position on a machine for carrying out the work.
It is more particularly directed to the case where a mechanical device is used to fit the holding part onto the eyeglass lens.
2. Description of the Prior Art
The present invention is even more particularly concerned with the case where, as in arrangements of the kind described in U.S. patent application Ser. No. 588 355 filed 26 Sept. 1990, now U.S. Pat. No. 5,070,657, the device employed for fastening a holding part on an eyeglass lens placed on a plate carried by a frame comprises an arm adapted to receive removably said holding part, a carriage on which said arm is able to provide between a raised loading end position and a lowered fitting end position and a frame on which said carriage is mobile in a straight line between a retracted rest end position and an advanced end of travel end position, drive means and a transmission operative between said carriage and/or said arm so that when the carriage is near its end of travel position the arm is in its retracted rest position.
In this way the pivoting of the arm and the displacement of the carriage advantageously result from the same movement imparted by the drive means, the arm reaching its fitting position before the carriage moves towards its end of travel position or during such movement, and normally returning to the loading position after the carriage has returned to its rest position.
This arrangement is satisfactory.
However, it is found that in some situations at least there may be some uncertainty as to the effective sequence of execution of the pivoting of the arm relative to the displacement of the carriage.
For example, if the arm is raised prematurely, as soon as the return movement of the carriage begins, for example, there is the risk of unwanted interference between the arm and the eyeglass lens on which it has just placed a holding part.
As a result the eyeglass lens may be dropped and broken.
A general object of the present invention is an arrangement allowing this drawback to be avoided and conferring other advantages.